The invention relates to mold cleaning apparatus.
After molding of epoxy resin material around a semiconductor chip and substrate, it is important to clean the mold halves before inserting the next substrate and semiconductor chip into the mold. Mold cleaning is important to ensure that foreign particles left on the mold cavities after the previous molded package have been removed and do not cause imperfections in subsequent molded packages.
Normally, the molding apparatus includes a first robotic carriage, commonly known as the on-loader carriage, which loads a substrate and semiconductor chip into the mold and a second robotic carriage, commonly known as the off-loader carriage, to remove the molded substrate and semiconductor chip from the mold. The mold cleaning is normally performed by a cleaning device which is mounted on the off-loader and which cleans the mold halves as the molded substrate and semiconductor chip are removed from the mold. After the mold halves have been cleaned by the off-loader carriage, the on-loader carriage then loads the next substrate and semiconductor chip to be molded into the mold.
One of the cleaning devices which is normally used to clean the mold halves is a suction device which sucks loose debris from both the upper and lower mold surfaces. The suction cleaning device normally includes an upper suction port, which engages with the upper mold half, and a lower suction port which engages with the lower mold half so that the upper and lower mold halves are cleaned simultaneously.
However, due to the influence of gravity, the majority of the mold debris accumulates on the lower mold half surface but it is easier to remove debris from the upper mold halves surface as gravity assists the removal of the mold debris from the upper mold halves. Hence, the conventional suction device has the disadvantage that it operates more efficiently in cleaning mold debris from the upper mold half but that the majority of the mold debris is located on the lower mold half.
In accordance with a first aspect of the present invention, there is provided mold cleaning apparatus compromising a manifold adapted to be coupled to a suction device, a first conduit extending from the manifold and having a first opening remote from the manifold, and a second conduit extending from the manifold and having a second opening remote from the manifold, the first and the second openings being directed in opposite directions, and the first conduit having a section with a cross-sectional area which is less than cross-sectional area at any point along the length of the second conduit
Preferably, the first opening is adapted to engage an upper mold surface of a mold and the second opening is adapted to engage a lower mold surface of a mold.
Preferably, the apparatus further comprises fluid injection means coupled to the second conduit, adjacent to the second opening, to inject fluid into the opening of the second conduit. Preferably, the fluid injection means is mounted on the second conduit to inject fluid towards the lower mold surface when the second opening is engaged with the lower mold surface.
Preferably, the apparatus comprises two manifolds and a conduit extends from each manifold to the first opening and from each manifold to the second opening.
Preferably, the first and the second openings each comprise a flexible member which is adapted to engage with the respective mold surface. Typically, the flexible member is an elastically deformable member.
In accordance with a second aspect of the present invention, there is provided a mold for molding a material around a semiconductor chip and a substrate on which the semiconductor chip is mounted, the mold comprising a lower mold half and an upper mold half, the mold halves being movable between an open position, in which a substrate and a semiconductor chip mounted thereon can be inserted into the mold halves and a molded substrate and semiconductor chip can be removed from the mold halves, and a closed position, in which a molding operation can be performed; a first movable carriage adapted to insert a substrate and a semiconductor chip mounted thereon into the mold; a second carriage adapted to remove a molded substrate and semiconductor chip from the mold, a first mold cleaning device mounted on the first carriage to clean a surface of the mold halves before a substrate and a semiconductor chip are placed in the mold; and a second cleaning device mounted on the second carriage to clean the mold halves after a molded substrate and semiconductor chip is removed from the mold.
Typically, the first cleaning device may comprise a brush and/or fabric which engages with a surface of the mold halves during cleaning.
Preferably, the first cleaning device cleans the lower mold half.
Preferably, the second mold cleaning device comprises a mold cleaning apparatus in accordance with the first aspect of the present invention.